(Bloomberg) -- Banco Santander SA said the Securities and Exchange Commission has started an inquiry into the use of unapproved messaging platforms at its US markets unit.

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“SanCap is cooperating with the SEC in connection with an inquiry focused on compliance with business-related communications on messaging platforms that were not approved by SanCap,” the lender said in a regulatory filing. “The inquiry follows a number of regulatory settlements with other firms covering similar matters.”

A Santander representative declined to comment.

US regulators have taken a close look in recent years how banks monitor employee communications. Twenty-six financial firms recently agreed to pay about $393 million in total fines after the SEC said they failed to keep records, Bloomberg reported. The payments added to the billions that big banks previously agreed to pay the SEC and the US Commodity Futures Trading Commission to settle similar investigations

Santander had previously decided to remove popular messaging platforms including WhatsApp from smartphones issued by the company to investment bankers in Spain, Bloomberg reported earlier this year. The use of this software had been banned, but some employees had kept the apps on their phones.

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